The present invention relates to a side airbag apparatus for deploying and inflating an airbag at the side of a passenger who is seated on a vehicle seat and protecting the passenger from an impact.
A side airbag apparatus of this type includes an airbag and an inflator. The airbag is incorporated in a seat back of a car seat in a folded state together with the inflator. For example, when an impact is given from the side to a side door of a car body, inflation gas is supplied from the inflator into the airbag. The airbag deploys and inflates forward from between the side door coming into a car and a passenger. As a result, the airbag restrains the passenger and mitigates an impact conveyed from the side to the passenger.
Japanese Patent Laid-Open No. 2012-162136 discloses a configuration in which an interior of an airbag is partitioned into two front and rear parts. As shown in FIGS. 19A and 20A, an airbag 121 is formed in a bag shape by joining margins of one pair of main body cloth portions 122 and 123. An inflator 124 is arranged at a rear end of the airbag 121 inside the airbag 121. The inflator 124 is attached to a seat frame 125 of a car seat via a locking member, such as a bolt, together with the main body cloth portion 122.
A longitudinal partition portion 126 having a communication hole (not shown) is laid between the two main body cloth portions 122 and 123. The airbag 121 is partitioned by the longitudinal partition portion 126 into a rear inflation chamber 127 and a front inflation chamber 128. The rear inflation chamber 127 is arranged behind the longitudinal partition portion 126. The rear inflation chamber 127 receives inflation gas supplied from the inflator 124. The front inflation chamber 128 is arranged in front of the longitudinal partition portion 126. The front inflation chamber 128 receives inflation gas supplied from the rear inflation chamber 127 through the communication hole. The longitudinal partition portion 126 is pulled at least at the time of inflation of the rear inflation chamber 127. The longitudinal partition portion 126 restricts an inflation thickness T1 which is a lateral thickness of the rear inflation chamber 127.
To increase the inflation thickness T1 of the rear inflation chamber 127, the position of the longitudinal partition portion 126 joined to the two main body cloth portions 122 and 123 needs to be shifted forward, as shown in FIG. 19B. The forward shift of the position of the longitudinal partition portion 126, however, increases a length L1 from a position of attachment of the airbag 121 to the seat frame 125 to a front end of the rear inflation chamber 127, as shown in FIG. 20B. This increases an amount by which the rear inflation chamber 127 protrudes, which may change the passenger-restraining capability and the passenger-protecting capability of the airbag.